Health monitoring of an electrochemical cell stack

Abstract

The present disclosure is directed towards a method and a system for monitoring the performance of an electrochemical cell stack. Monitoring can be performed remotely by measuring the voltage across the stack, and comparing the measured values to predetermined reference values to determine the condition of the stack. Monitoring of the stack voltage enables detection of performance decay, which in turn enables preemptive repair of the stack prior to catastrophic failure.

What is claimed is: 
     
         1 . A method of monitoring an electrochemical cell, comprising:
 conducting a linear current sweep across the cell;   measuring the pressure at an inlet (P in ) and at an outlet (P out ) of the cell;   generating a baseline voltage-current (V-I) curve of the cell and calculating a slope of the baseline V-I curve;   generating an aged V-I curve of the cell at any time point during operation of the cell using a predetermined ratio of pressures of P in  and P out  and calculating a slope of the aged V-I curve;   calculating a difference in value between the slopes of the baseline V-I curve and the aged V-I curve; and   comparing the difference in value between the slopes of the baseline V-I curve and the aged V-I curve to a preset reference value.   
     
     
         2 . The method of  claim 1 , further comprising alerting an operator of the cell if the difference in value between the slopes of the baseline V-I curve and the aged V-I curve is greater than the preset reference value. 
     
     
         3 . The method of  claim 1 , further comprising initiating automatic corrective actions if the difference in value between the slopes of the baseline V-I curve and the aged V-I curve is greater than the preset reference value. 
     
     
         4 . The method of  claim 1 , further comprising shutting down the electrochemical cell if the difference in value between the slopes of the baseline V-I curve and the aged V-I curve is greater than the preset reference value. 
     
     
         5 . A method of monitoring an electrochemical cell, comprising:
 measuring a voltage required to deliver a given current through the cell at the beginning of the cell's life to establish a baseline voltage;   measuring the pressure at an inlet (P in ) and at an outlet (P out ) of the cell;   measuring a voltage required to deliver a given current through the cell at any time point during operation of the cell to establish an aged voltage;   calculating a difference between the baseline voltage and the aged voltage at a predetermined ratio of pressures of P in  and P out ; and   comparing the difference in value between the baseline voltage and the aged voltage to a preset reference value.   
     
     
         6 . The method of  claim 5 , further comprising alerting an operator of the cell if the difference in value between the baseline voltage and the aged voltage is greater than the preset reference value. 
     
     
         7 . The method of  claim 5 , further comprising initiating automatic corrective actions if the difference in value between the baseline voltage and the aged voltage is greater than the preset reference value. 
     
     
         8 . The method of  claim 5 , further comprising shutting down the electrochemical cell if the difference in value between the baseline voltage and the aged voltage is greater than the preset reference value.